DJ-Catalog2 Joomla component allows to display products in blog layout in many columns but if you want to change the default number of products you can do it in 2 ways.

Change it in the global configuration and use for all blog views.

Navigate Components -> DJ-Catalog2 and then press Options button 

Then choose:

1. Category View - Item tab 
2. select the the value for Product per Page parameter 

 

Change it for the specified menu item only.

Let's take for example JM-Hiking template. The DJ-Catalog2 component is assigned to the Home Page, so navigate Menus -> About Joomla -> edit Home item

and then select the number of products: